A343188 a(1) = a(2) = a(3) = 1; a(n+3) = Sum_{d|n} mu(n/d) * a(d).

1, 1, 1, 1, 0, 0, 0, -1, -1, -1, -2, -2, -1, -3, -2, -2, -3, -2, -1, -4, 0, -2, -3, 0, 0, -4, 4, 0, -3, 5, 3, -4, 9, 2, -2, 11, 5, -1, 15, 4, 0, 16, 10, -1, 20, 9, 1, 24, 12, 0, 25, 12, 1, 28, 16, 0, 25, 19, 2, 26, 22, 1, 26, 21, -2, 28, 25, 0, 20, 24, -2, 23, 30, -3, 10

Offset: 1

Author

Ilya Gutkovskiy, Apr 07 2021

Keywords

• sign

Crossrefs

Cf. A007554, A307993, A318583, A343189, A343190.

Programs

Mathematica

a[1] = a[2] = a[3] = 1; a[n_] := a[n] = Sum[MoebiusMu[(n - 3)/d] a[d], {d, Divisors[n - 3]}]; Table[a[n], {n, 75}]